NMF Hyperspectral Unmixing Of The Sea Bottom: Influence Of The Adjacency Effects, Model and Method

International audienceSea bottom unmixing is a challenging task for the analysis of coastal zones. Actually the upward photons are attenuated and diffused by the water column layer, giving low signal to noise hyperspectral data. A classical approach is to perform inversion of the water column using semi-analytical parametric models and estimation process, and obtain the water column constituents (chlorophyll, suspended matter, dissolved organic matter and bathymetry), and the coefficients of pure materials reflectance spectra (endmembers), given in spectral libraries, for each pixel. We consider here the case of unknown endmembers, and we suppose that the water column components have been obtained by a classical inversion method or in-situ measurements. For each observed pixel the upward luminance is analysed and decomposed into three terms, respectively issued after interaction with the target bottom pixel, its neighbours, and the water column. We show that in some conditions the adjacent pixels effect is not negligible, due to the diffusion in the water column, and we develop in accordance a new mixing model for the sea bottom. We propose a non-negative matrix factorisation based unmixing method to solve the problem, and present results for hyperspectral data simulations

Laparoscopic paracostal herniorrhaphy in a dog: case report

Traumatic paracostal hernia is classified as an abdominal hernia that protrudes from the abdomen to a non physiologic space over the ribs. Treatment requires surgical reconstruction of the disrupted musculature in the thoracoabdominal region. Laparoscopic paracostal herniorrhaphy was performed in an eight-month-old male Teckel, presented after a car accident injury. A three-portal laparoscopic access was used for definitive diagnosis and hernia correction. After traction of the herniated omentum, a thoracoabdominal communication caused a left side pneumothorax, which was successfully drained with a chest tube placement. The herniorrhaphy was accomplished with intracorporeal sutures by a combination of Ford interlocking and cross mattress patterns. The postoperative period was uneventful. The laparoscopic paracostal herniorrhaphy was satisfactory, allowing both diagnosis and correction of the paracostal defect, showing to be a feasible alternative to the open surgery